Bridge reducing mixed-flow grain dryer with cross-flow vacuum cool heat recovery system

ABSTRACT

An improved grain dryer is presented having a mixed-flow heating section having a plurality of inlet ducts connected to the plenum that facilitate air flow into the grain column from the heated and pressurized heat plenum, and a plurality of exhaust ducts connected to openings in the exterior wall that facilitate air flow out of the grain column. Outer most ducts of the inlet and exhaust ducts, which are positioned closest to end walls of the grain column, are configured to reduce bridging or grain between the outer most ducts and the end walls of the grain column.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation in part of U.S. Utility applicationSer. No. 16/258,158 which was filed on Jan. 25, 2019 entitled“MIXED-FLOW GRAIN DRYER WITH CROSS-FLOW VACUUM COOL HEAT RECOVERYSYSTEM”, which is a continuation in part of U.S. Utility applicationSer. No. 15/131,865 which was filed on Apr. 18, 2016, the entirety ofwhich is incorporated herein fully by reference herein.

This application claims priority to U.S. Provisional Patent Applications62/937,627, which was filed on Nov. 19, 2019 entitled “BRIDGE REDUCINGMIXED-FLOW GRAIN DRYER WITH CROSS-FLOW VACUUM COOL HEAT RECOVERYSYSTEM”, the entirety of which is incorporated herein fully by referenceherein.

FIELD OF THE DISCLOSURE

This disclosure relates to generally to the grain handling, grainstorage and grain conditioning arts. More specifically and withoutlimitation, this disclosure relates to the grain drying arts. Morespecifically and without limitation, this disclosure relates to animproved grain dryer and grain drying system known as a mixed-flow graindryer with a cross-flow vacuum cool heat recovery system.

OVERVIEW

Grain dryers are old and well known in the art. Grain dryers arecommonly used to dry various types of grain, such as corn, wheat, rice,sorghum, and the like, so as to allow the grain to be stored in bulk,such as in a grain bin, tote or other bulk grain storage device, forextended periods of time. If grain is stored in bulk with a moisturecontent that is too high, the grain will spoil. As such, particular careis taken to ensure that grain that is to be stored does not too high amoisture content.

Optimally drying grain is a particularly complex, difficult and delicatematter. Care must be taken to ensure that the grain is dried enough tohave a low enough moisture content to ensure that it does not spoilwhile being stored. However, it is also undesirable to overly dry grain.

Overly drying grain is wasteful in various ways. Overly drying grainconsumes additional and unnecessary fuel used to dry the grain beyondthe moisture content level that is needed for stable storage. Overlydrying grain often takes additional and unnecessary time to dry thegrain beyond the moisture content level that is needed for stablestorage. Overly drying grain can damage the grain by causing it to beburned, cracked or otherwise damaged, which can reduce the value of thegrain. Overly drying grain can reduce the test weight of the grainthereby causing a deduction in the price of the grain when it is sold.For these and other reasons, overly drying grain is undesirable.

As such, optimally drying grain requires striking a delicate balancebetween overly drying grain on one side, and not drying grain enough onthe other side.

Various configurations of grain dryers have been developed to helpfacilitate efficient grain drying. However, all of the presentlyavailable grain dryers suffer from various disadvantages.

Cross-Flow Grain Dryers: One form of a grain dryer is what is known as across-flow grain dryer. Cross-flow grain dryers are known for having apair of grain columns on each side that are formed by perforatedscreens. A plenum, or open space, is positioned between the graincolumns. Wet grain is loaded into the grain columns using a loadingsystem. The wet grain travels down the grain columns under the force ofgravity, between the perforated screens. As the wet grain travels downthe grain columns, between the perforated screens, heated air is blowninto the plenum. This heated air flows outward from the plenum andthrough the columns of grain. As the heated air blows through thecolumns of grain, the heated air warms the grain and carries awaymoisture from the grain. Dry grain is unloaded from the grain columnsusing an unloading system. In this way, the grain is dried.

Cross-flow grain dryers suffer from many disadvantages. One disadvantageof cross-flow grain dryers is that they are relatively harsh on grain.This is because the grain toward the interior side of the grain columnsis often exposed to high levels of heat which can cause theinterior-positioned grain to crack, burn, and/or be overly dried.Another disadvantage of cross-flow grain dryers is that the grain withinthe grain columns tends to dry in an uneven manner. That is, the grainpositioned toward the interior side of the grain column has a tendencyto be dried more than the grain positioned toward the exterior side ofthe grain column. Another disadvantage of cross-flow is that they tendto require relatively high operating pressures and high air-flow.Another disadvantage of cross-flow grain dryers is that they tend toconsume a lot of fuel, or said another way they are energy inefficient.Another disadvantage of cross-flow grain dryers is the screens tend toget covered and plugged with fines from the grain which affects theoperational characteristics of the grain dryer as well as requiresperiodic cleaning.

For these and other reasons, cross-flow grain dryers suffer from manydisadvantages and are undesirable to use.

Mixed-Flow Grain Dryers: One form of a grain dryer is what is known as amixed-flow grain dryer. Mixed-flow grain dryers are known for having apair of grain columns on each side that have a plurality inlet ducts andexhaust ducts that extend across the grain column. A plenum, or openspace, is positioned between the grain columns. Wet grain is loaded intothe grain columns using a loading system. The wet grain travels down thegrain columns under the force of gravity. As the wet grain travels downthe grain columns, between the interior wall and exterior wall of thegrain columns, heated air is blown into the plenum. This heated airflows into the inlet ducts through the columns of grain and out theexhaust ducts. As the heated air blows through the columns of grain, theheated air warms the grain and carries away moisture from the grain. Drygrain is unloaded from the lower end of each of the grain columns usingan unloading system. In this way, the grain is dried.

Mixed-flow grain dryers suffer from many disadvantages. One disadvantageof mixed-flow grain dryers is that they do not allow for heat recoveryand as such they waste energy and consume unnecessary fuel. Anotherdisadvantage of mixed-flow grain dryers is that each column requires itsown unload system. Another disadvantage of mixed-flow grain dryers isthat they are susceptible to bridging of grain in grain columns.

For these and other reasons, mixed-flow grain dryers suffer from manydisadvantages and are undesirable to use.

Therefore, for all the reasons stated above, and the reasons statedbelow, there is a need in the art for a grain drying system thatimproves upon the state of the art.

Thus, it is a primary objective of the disclosure to provide a graindryer system that improves upon the state of the art.

Another object of the disclosure is to provide a grain dryer system thatis efficient to use.

Yet another object of the disclosure is to provide a grain dryer systemthat facilitates heat recovery.

Another object of the disclosure is to provide a grain dryer system thatreduces fuel consumption.

Yet another object of the disclosure is to provide a grain dryer systemthat is gentle on grain.

Another object of the disclosure is to provide a grain dryer system doesnot damage grain when drying.

Yet another object of the disclosure is to provide a grain dryer systemthat does not overly dry grain.

Another object of the disclosure is to provide a grain dryer system thatfacilitates cooling of grain before it is discharged.

Yet another object of the disclosure is to provide a grain dryer systemthat evenly dries grain.

Another object of the disclosure is to provide a grain dryer system thatdoes not have variability of grain quality across the grain column.

Yet another object of the disclosure is to provide a grain dryer systemthat does not have variability of moisture across the grain column.

Another object of the disclosure is to provide a grain dryer system thatcan be precisely controlled.

Yet another object of the disclosure is to provide a grain dryer systemthat provides optimum results.

Another object of the disclosure is to provide a grain dryer system thatfacilitates unloading of grain from the dryer at a single point.

Yet another object of the disclosure is to provide a grain dryer systemthat is relatively compact.

Another object of the disclosure is to provide a grain dryer system thatis relatively inexpensive.

Yet another object of the disclosure is to provide a grain dryer systemthat can be used with all kinds of grain.

Another object of the disclosure is to provide a grain dryer system thatthat minimizes maintenance.

Yet another object of the disclosure is to provide a grain dryer systemthat requires less cleaning.

Another object of the disclosure is to provide a grain dryer system thatis cleaner to use than prior art systems.

Yet another object of the disclosure is to provide a grain dryer systemthat is safe to use.

Another object of the disclosure is to provide a grain dryer system thatreduces the potential for a fire.

Yet another object of the disclosure is to provide a grain dryer systemthat requires less air pressure.

Another object of the disclosure is to provide a grain dryer system thatrequires less air flow.

Yet another object of the disclosure is to provide a grain dryer systemthat provides improved grain quality.

Another object of the disclosure is to provide a grain dryer system thatis easy to use.

Yet another object of the disclosure is to provide a grain dryer systemthat has a robust design.

Another object of the disclosure is to provide a grain dryer system thatis high quality.

Yet another object of the disclosure is to provide a grain dryer systemthat incorporates the benefits of mixed-flow grain dying with thebenefits of cross-flow vacuum cooling.

Another object of the disclosure is to provide a grain dryer system thatprovides a unique solution to grain drying needs.

Yet another object of the disclosure is to provide a grain dryer systemthat reduces bridging of grain.

SUMMARY OF THE DISCLOSURE

An improved mixed-flow grain dryer with cross-flow vacuum cool heatrecovery system is presented. The grain dryer system includes a loadingsystem positioned at its upper end and an unloading system positioned atits lower end. Once loaded into the dryer, grain passes through thegrain dryer under the force of gravity in a grain column positioned oneach side of a centrally positioned plenum. A wet holding section ispositioned at the upper end of the grain dryer and receives wet grainfrom the loading system. The wet holding section directs the grain intothe grain columns. A heating section is positioned just below the wetholding section and receives wet grain from the wet grain section. Thegrain column of the heating section is formed by a solid interior walland a solid exterior wall. A plurality of inlet ducts is connected toopenings in the interior wall that facilitate air flow into the graincolumn from the heated and pressurized heat plenum. A plurality ofexhaust ducts is connected to openings in the exterior wall thatfacilitate air flow out of the grain column. In this way, air flows fromthe heated and pressurized heat plenum, through the openings in theinterior wall and into the connected inlet duct, through the graincolumn, into the exhaust ducts and out the connected openings in theexterior wall. In this way, the heated and pressurized air in the heatplenum gently flows through the grain column thereby heating and dryingthe grain. A tempering section is positioned just below the heatingsection and receives heated and dried grain from the heating section.The tempering section has a solid interior wall and a solid exteriorwall that prevents air flow through the grain column in the temperingsection. A cooling section is positioned just below the temperingsection and receives heated and dried grain from the tempering section.The grain column of the cooling section is formed by a perforatedinterior wall and a perforated exterior wall. Air is pulled through theperforated exterior wall, through the grain column and through theperforated interior wall and into the cool plenum under vacuum formed bya fan connected to the cool plenum of the cooling section. As the air ispulled through the grain column of the cooling section, the grain iscooled and the air is heated. An unloading system is positioned justbelow the cooling section and receives cooled and dried grain from thecooling section. The unloading system unloads the grain from the draindryer system. A fan having adjustable louvers is connected to the coolplenum of the cooling section. The fan pulls air through the graincolumn of the cooling section which heats the air while cooling thegrain. This heated air is heated further by a heater. This heated air isthen blown into the heat plenum thereby pressurizing the heat plenum. Inthis way, a mixed-flow grain dryer with cross-flow vacuum cool ispresented that harnesses the benefits of mixed-flow heating andcross-flow vacuum cooling that provides gentler drying and increasedefficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side sectional view of a mixed-flow grain dryer withcross-flow vacuum cool heat recovery system.

FIG. 2 is a perspective sectional view of a mixed-flow grain dryer withcross-flow vacuum cool heat recovery system.

FIG. 3 is a perspective view of a mixed-flow grain dryer with cross-flowvacuum cool heat recovery system.

FIG. 4 is a close up view of the upper end of FIG. 1.

FIG. 5 is a close up view of the middle portion of FIG. 1, the viewshowing the mixed-flow heating section.

FIG. 6 is a close up view of the upper portion of FIG. 5, the viewshowing the upper portion of the mixed-flow heating section.

FIG. 7 is a close up view of the lower portion of FIG. 5, the viewshowing the lower portion of the mixed-flow heating section.

FIG. 8 is a close up view of the lower portion of FIG. 1.

FIG. 9 is a close up view of the lower portion of FIG. 8.

FIG. 10 is a close up view of the upper portion of FIG. 2.

FIG. 11 is a close up view of the middle portion of FIG. 2.

FIG. 12 is a close up view of the lower portion of FIG. 2.

FIG. 13 is a close up view of the middle portion of the left side ofFIG. 2.

FIG. 14 is a close up view of the middle portion of the right side ofFIG. 2.

FIG. 15 is a close up view of the upper portion of FIG. 3.

FIG. 16 is a close up view of the upper right portion of FIG. 3.

FIG. 17 is a close up view of the middle left portion of FIG. 3.

FIG. 18 is a close up view of the lower left portion of FIG. 3.

FIG. 19 is a view of the interior of a grain column of a mixed florgrain dryer; the view showing inlet and exhaust duct with bridged grainstuck between the outer most ducts and the end walls of the graincolumn.

FIG. 20 is an exterior upper left perspective view of grain column of amixed flor grain dryer; the view showing inlet and exhaust ducts and theexterior wall.

FIG. 21 is an interior upper right perspective view of grain column of amixed flor grain dryer; the view showing inlet and exhaust ducts and theexterior wall.

FIG. 22 is an interior rear view of grain column of a mixed flor graindryer; the view showing inlet and exhaust ducts and the exterior wall.

FIG. 23 is an interior rear upper perspective view of grain column of amixed flor grain dryer; the view showing inlet and exhaust ducts and theexterior wall.

FIG. 24 is an exterior upper right perspective view of grain column of amixed flor grain dryer; the view showing inlet and exhaust ducts and theexterior wall.

FIG. 25 is an interior upper left perspective view of grain column of amixed flor grain dryer; the view showing inlet and exhaust ducts and theexterior wall.

DETAILED DESCRIPTION OF THE DISCLOSURE

In the following detailed description of the embodiments, reference ismade to the accompanying drawings which form a part hereof, and in whichis shown by way of illustration specific embodiments in which thedisclosure may be practiced. The embodiments of the present disclosuredescribed below are not intended to be exhaustive or to limit thedisclosure to the precise forms in the following detailed description.Rather, the embodiments are chosen and described so that others skilledin the art may appreciate and understand the principles and practices ofthe present disclosure. It will be understood by those skilled in theart that various changes in form and details may be made withoutdeparting from the principles and scope of the invention. It is intendedto cover various modifications and similar arrangements and procedures,and the scope of the appended claims therefore should be accorded thebroadest interpretation so as to encompass all such modifications andsimilar arrangements and procedures. For instance, although aspects andfeatures may be illustrated in or described with reference to certainfigures or embodiments, it will be appreciated that features from onefigure or embodiment may be combined with features of another figure orembodiment even though the combination is not explicitly shown orexplicitly described as a combination. In the depicted embodiments, likereference numbers refer to like elements throughout the variousdrawings.

It should be understood that any advantages and/or improvementsdiscussed herein may not be provided by various disclosed embodiments,or implementations thereof. The contemplated embodiments are not solimited and should not be interpreted as being restricted to embodimentswhich provide such advantages or improvements. Similarly, it should beunderstood that various embodiments may not address all or any objectsof the disclosure or objects of the invention that may be describedherein. The contemplated embodiments are not so limited and should notbe interpreted as being restricted to embodiments which address suchobjects of the disclosure or invention. Furthermore, although somedisclosed embodiments may be described relative to specific materials,embodiments are not limited to the specific materials or apparatuses butonly to their specific characteristics and capabilities and othermaterials and apparatuses can be substituted as is well understood bythose skilled in the art in view of the present disclosure.

It is to be understood that the terms such as “left, right, top, bottom,front, back, side, height, length, width, upper, lower, interior,exterior, inner, outer, and the like as may be used herein, merelydescribe points of reference and do not limit the present invention toany particular orientation or configuration.

As used herein, the term “or” includes one or more of the associatedlisted items, such that “A or B” means “either A or B”. As used herein,the term “and” includes all combinations of one or more of theassociated listed items, such that “A and B” means “A as well as B.” Theuse of “and/or” includes all combinations of one or more of theassociated listed items, such that “A and/or B” includes “A but not B,”“B but not A,” and “A as well as B,” unless it is clearly indicated thatonly a single item, subgroup of items, or all items are present. The useof “etc.” is defined as “et cetera” and indicates the inclusion of allother elements belonging to the same group of the preceding items, inany “and/or” combination(s).

As used herein, the singular forms “a,” “an,” and “the” are intended toinclude both the singular and plural forms, unless the languageexplicitly indicates otherwise. Indefinite articles like “a” and “an”introduce or refer to any modified term, both previously-introduced andnot, while definite articles like “the” refer to a samepreviously-introduced term; as such, it is understood that “a” or “an”modify items that are permitted to be previously-introduced or new,while definite articles modify an item that is the same as immediatelypreviously presented. It will be further understood that the terms“comprises,” “comprising,” “includes,” and/or “including,” when usedherein, specify the presence of stated features, characteristics, steps,operations, elements, and/or components, but do not themselves precludethe presence or addition of one or more other features, characteristics,steps, operations, elements, components, and/or groups thereof.

It will be understood that when an element is referred to as being“connected,” “coupled,” “mated,” “attached,” “fixed,” etc. to anotherelement, it can be directly connected to the other element, and/orintervening elements may be present. In contrast, when an element isreferred to as being “directly connected,” “directly coupled,” “directlyengaged” etc. to another element, there are no intervening elementspresent. Other words used to describe the relationship between elementsshould be interpreted in a like fashion (e.g., “between” versus“directly between,” “adjacent” versus “directly adjacent,” “engaged”versus “directly engaged,” etc.). Similarly, a term such as“operatively”, such as when used as “operatively connected” or“operatively engaged” is to be interpreted as connected or engaged,respectively, in any manner that facilitates operation, which mayinclude being directly connected, indirectly connected, electronicallyconnected, wirelessly connected or connected by any other manner, methodor means that facilitates desired operation. Similarly, a term such as“communicatively connected” includes all variations of informationexchange and routing between two electronic devices, includingintermediary devices, networks, etc., connected wirelessly or not.Similarly, “connected” or other similar language particularly forelectronic components is intended to mean connected by any means, eitherdirectly or indirectly, wired and/or wirelessly, such that electricityand/or information may be transmitted between the components.

It will be understood that, although the ordinal terms “first,”“second,” etc. may be used herein to describe various elements, theseelements should not be limited to any order by these terms unlessspecifically stated as such. These terms are used only to distinguishone element from another; where there are “second” or higher ordinals,there merely must be a number of elements, without necessarily anydifference or other relationship. For example, a first element could betermed a second element, and, similarly, a second element could betermed a first element, without departing from the scope of exampleembodiments or methods. Similarly, the structures and operationsdiscussed herein may occur out of the order described and/or noted inthe figures. For example, two operations and/or figures shown insuccession may in fact be executed concurrently or may sometimes beexecuted in the reverse order, depending upon the functionality/actsinvolved. Similarly, individual operations within example methodsdescribed below may be executed repetitively, individually orsequentially, to provide looping or other series of operations asidefrom single operations described below. It should be presumed that anyembodiment or method having features and functionality described below,in any workable combination, falls within the scope of exampleembodiments.

As used herein, various disclosed embodiments may be primarily describedin the context of agricultural grain dryers. However, the embodimentsare not so limited. It is appreciated that the embodiments may beadapted for use in other agricultural implements and in otherapplications, which may be improved by the disclosed structures,arrangements and/or methods. The system is merely shown and described asbeing used in the context of agricultural grain dryers for ease ofdescription and as one of countless examples.

System:

With reference to the figures, a mixed-flow grain dryer with cross-flowvacuum cool heat recovery system 10, mixed flow grain dryer 10, orsimply system 10, is presented that extends vertically from an upper end12 to a lower end 14, extends a width between opposing sides 16, andextends a depth between an opposing forward end 18 and an opposingrearward end 20. Mixed-flow grain dryer with cross-flow vacuum cool heatrecovery system 10 is formed of any suitable size, shape and design andis configured to gently and efficiently cool grain while providing asingle loading point, a single unloading point and heat recovery. In thearrangement shown, as one example, system 10 includes a pair of graincolumns 22 having an exterior wall 24 and an interior wall 26 separatedby a plenum 28, a loading system 30, a wet hold section 32, a mixed-flowheating section 34, a tempering section 36, a cross-flow cooling section38, an unloading system 40, an air handling system 42 having a fansystem 44, a heating system 46 and louvers 48, and a support system 50,among other components, structures and features as is further describedherein.

In the arrangement shown, as one example, to facilitate even air flowacross the system 10, the system 10 is generally symmetric along avertically extending line that runs through the center of the system 10between opposing sides 16.

Grain Columns:

In the arrangement shown, as one example, mixed-flow grain dryer withcross-flow vacuum cool heat recovery system 10 includes at least onegrain column 22. Grain columns 22 are formed of any suitable size, shapeand design and are configured to hold grain therein while the grainmoves vertically through the system 10 under the force of gravity whilebeing exposed to heating of the mixed-flow heating section 34 andcooling of the cross-flow cooling section 38.

In the arrangement shown, as one example system 10 includes a pair ofgrain columns 22, with one grain column 22 positioned on each side 16 ofsystem 10. In the arrangement shown, as one example, grain columns 22extend laterally a width and are bounded on one side by exterior wall 24and bounded on the opposite side by interior wall 26. Grain columns 22are bounded at their ends by end walls 52. The interior sides of graincolumns 22 are separated by plenum 28. The exterior sides of graincolumns 22 connect with the atmosphere surrounding system 10.

In the arrangement shown, as one example, grain columns 22 extendvertically from the lower end of loading system 30 to the upper end ofunloading system 40 in a continuous and uninterrupted manner. In thisway, when grain enters one of the two of the opposing grain columns 22,the grain travels vertically through the grain column 22 from its upperend to its lower end under the force of gravity while being exposed tothe air flow of mixed-flow heating section 34 and cross-flow coolingsection 38.

In the arrangement shown, as one example, the grain columns 22 are widerat the mixed-flow heating section 34 than they are at the cross-flowcooling section 38. In the arrangement shown, as one example, the widthof grain columns 22 remains generally constant and consistent throughoutthe length of the heating section 34. In the arrangement shown, as oneexample, the width of grain columns 22 remains generally constantthroughout the length of the cooling section 38, albeit with a turn orangle positioned within the cooling section 38. In the arrangementshown, as one example, tempering section 36 narrows the width of thegrain columns 22 by angling the interior wall 26 and exterior wall 24toward one another such that tempering section 36 transitions the widthof the grain column 22 from the wider heating section 34 to the narrowercooling section 38.

While two opposing grain columns 22 are shown in use with system 10, anynumber of grain columns 22 are hereby contemplated for use such as one,two, three, four, five, six or more. As any other shape or configurationof grain columns 22.

Plenum:

In the arrangement shown, as one example, mixed-flow grain dryer withcross-flow vacuum cool heat recovery system 10 includes a plenum 28.Plenum 28 is formed of any suitable size, shape and design and isconfigured to provide a space between grain columns 22 so as tofacilitate airflow through grain columns 22.

In the arrangement shown, as one example plenum 28 is a generallycentrally positioned space that extends between the opposing interiorwalls 26 of grain columns 22 and extends between the interior surfacesof end walls 52. In the arrangement shown, as one example, the upper endof plenum 28 is bounded by the angled lower walls of wet hold section32. In the arrangement shown, as one example, the lower end of plenum 28is bounded by the angled upper walls 56 of unloading system 40 and/ordivider 58 positioned adjacent upper walls 56 of unloading system 40. Inthis way, plenum 28 extends the entire interior height of system 10.

In the arrangement shown, as one example, a divider 60 extends acrossplenum 28. Divider 60 separates plenum 28 into a heat plenum 62, whichis positioned above divider 60, and a cool plenum 64, which ispositioned below divider 60.

Heat Plenum: Heat plenum 62 is formed of any suitable size, shape anddesign and is configured to receive heated air from air handling system42 which is blown outward through the grain column 22 of the heatingsection 34. In the arrangement shown, as one example, heat plenum 62 isbounded on its lower end by divider 60, is bounded on its exterior sidesby interior walls 26 of heating section 34, is bounded on its upper endby lower walls 54 of wet hold section 32, and is bounded at its ends byinterior surfaces of end walls 52. In the arrangement shown, as oneexample, the width of heat plenum 62 remains generally constant from itsupper end to its lower end, albeit with a peak at its upper end formedby the angled lower walls 54 of wet hold section 32.

In the arrangement shown, as one example, a plurality of structuralmembers 66 extend across heat plenum 62. Structural members 66 areformed of any suitable size, shape and design and are configured toconnect the opposing sides of system 10 so as to provide structuralsupport and rigidity and strength to the large and tall system 10. Inthe arrangement shown, as one example, a plurality of structural members66 extend between opposing interior walls 26 of heat plenum 62. Morespecifically, in the arrangement shown, three sets of three structuralmembers 66 are placed in an X-formation with a centrally extendingstructural member 66 extending through the center of each X-formation.In this way, structural members 66 bridge the width of heat plenum 62thereby connecting opposing interior sides of heat plenum 62 while notinhibiting air flow through heat plenum 62. Any other configuration ofstructural members 66 is hereby contemplated for use.

In the arrangement shown, as one example, heat plenum 62 is connected toand receives output from air handling system 42, or more specificallyfan system 44 and heating system 46. In this way, heat plenum 62receives heated and pressurized air from air handling system 42. Thisheated and pressurized air is pushed or blown outward through the graincolumn of mixed-flow heating section 34 as is further described herein.

Cool Plenum: Cool plenum 64 is formed of any suitable size, shape anddesign and is configured to receive vacuum from air handling system 42which causes air to be pulled through the grain column 22 of the coolingsection 38 and into cool plenum 64. In the arrangement shown, as oneexample, cool plenum 64 is bounded on its upper end by divider 60, isbounded on its exterior sides by interior walls 26 of cooling section38, is bounded on its lower end by upper walls 56 of unloading system 40as well as divider 58, and is bounded at its ends by interior surfacesof end walls 52. In the arrangement shown, as one example, the width ofcool plenum 64 varies as the interior wall 26 angles outward at theupper end of tempering section 36, extends vertically at the upper endof cooling section 38, angles inward at the lower end of cooling section38, and is bounded at its lower end by the upper surface of divider 58that extends in generally parallel spaced relation to divider 60.

In the arrangement shown, as one example, cool plenum 64 does notinclude any structural members 66 that extend across the cool plenum 64.In an alternative arrangement, cool plenum 64 includes one or morestructural members 66 that extend across cool plenum 64 similar to theheat plenum 62.

In the arrangement shown, as one example, cool plenum 64 is connected tothe input of air handling system 42, or more specifically fan system 44.In this way, cool plenum 64 feeds air into air handling system 42 andtherefore cool plenum 64 is under vacuum or negative pressure. Thevacuum or negative pressure of cool plenum 64 causes air to be drawn,pulled or sucked through the grain column of cross-flow cooling section38 as is further described herein.

Loading System:

In the arrangement shown, as one example, mixed-flow grain dryer withcross-flow vacuum cool heat recovery system 10 includes a loading system30. Loading system 30 is formed of any suitable size, shape and designand is configured to facilitate loading of wet grain into system 10.

Any form of a grain loading system is hereby contemplated for use asloading system 30. In the arrangement shown, as one example loadingsystem 30 is an auger system having an input 68, that receives grainfrom a chute or other device. A shaft 70 with flighting 71 extendsacross the upper end of system 10. The shaft 70 with fighting 71 isconnected to a motor 72 by a pulley and belt system and is configured torotate the shaft 70 with flighting 71. A housing 74 is positioned overand around the shaft 70 with fighting 71 so as to constrain the grainmoved by the shaft 70 with fighting 71. In the arrangement shown,housing 74 is generally square or rectangular with an open lower endthat connects to wet hold section 32 so as to facilitate the transfer ofgrain from the loading system 30 to the wet hold section 32.

In operation, as motor 72 operates, while grain is loaded into loadingsystem 30, the shaft 70 with flighting 71 rotates thereby moving thegrain across the upper end of system 10 evenly distributing wet grainacross the upper end of system 10, or more specifically across the upperend of wet hold section 32. In the arrangement shown, as one example, asensor 76 is positioned adjacent one end of loading system 30, or morespecifically adjacent one end of shaft 70 with fighting 71. When loadingsystem 30 and/or wet hold section 32 is filled with grain, sensor 76detects this filled condition. This information is then used to stop therotation of loading system 30 and/or to stop loading grain into input 68and/or to shut down or stop any other component of the system. Once thegrain is consumed from the area around sensor 76, loading system 30 mayagain resume operation and the loading of grain. In the arrangementshown, as one example, one or more sensors 76 are positioned on an endof shaft 70 with flighting 71 opposite input 68.

While in the arrangement shown, only a single auger, or shaft 70 withflighting 71 is used, it is hereby contemplated that multiple augers ormultiple shafts 70 with fighting 71 are used in loading system 30. Also,while in the arrangement shown, the input 68 is positioned adjacent oneend of the loading system 30 and the sensor 76 is positioned adjacentthe opposite end of the loading system 30, it is hereby contemplatedthat grain may be loaded at the middle of loading system 30 and movedoutward to the ends using shaft 70 with flighting 71. Alternatively, agravity fill system is hereby contemplated for use. Alternatively, abelt, a conveyor, a paddle sweep and/or a drag chain system is herebycontemplated for use as loading system 30. Any other structure orconfiguration of a system for loading grain is hereby contemplated foruse as loading system 30.

Wet Hold Section:

In the arrangement shown, as one example, mixed-flow grain dryer withcross-flow vacuum cool heat recovery system 10 includes a wet holdsection 32. Wet hold section 32 is formed of any suitable size, shapeand design and is configured to hold and stage a quantity of wet grainprior to the grain passing through the grain columns 22.

In the arrangement shown, as one example, wet hold section 32 connectsat its upper end to the lower end of loading system 30 and connects atits lower end to the upper end of mixed-flow heating section 34. In thearrangement shown, as one example, wet hold section 32 starts theformation of grain columns 22.

In the arrangement shown, as one example, the upper side of wet holdsection 32 includes upper side walls 78 and upper end walls 80 thatenclose the upper end of wet hold section 32. In the arrangement shown,as one example, upper side walls 78 connect at their upper end to thelower end of the sides of housing 74 of loading system 30, and upperside walls 78 connect at their lower end to the upper end of exteriorwalls 24. Similarly, in the arrangement shown, as one example, upper endwalls 80 connect at their upper end to the lower end of the ends ofhousing 74 of loading system 30, and upper end walls 80 connect at theirlower end to the upper end of end walls 52. In the arrangement shown, asone example, upper side walls 78 and upper end walls 80 extend downwardat an angle as they extend outward thereby forming a sloped roof at theupper end of system 10.

In the arrangement shown, as one example, a door 82 is positioned in oneor both upper end walls 80. Door 82 is formed of any suitable size,shape and design and is configured to provide access to the hollowinterior of wet hold section 32 so as to facilitate repair and cleaningof the components of wet hold section 32. Additional doors 82 may beplaced in other parts wet hold section 32, such as upper side walls 78,or for that matter in any other part of system 10 such as the interiorwall 26 of grain columns 22 as well as any other place or position.

In the arrangement shown, as one example, the lower side of wet holdsection 32 includes lower walls 54 that enclose the lower end of wethold section 32. In the arrangement shown, as one example, lower walls54 connect at their upper end to one another thereby forming a peak atthe approximate upper center end of plenum 28. This peak divides ordirects the grain held within wet hold section 32 into one or the othergrain columns 22. Similarly, in the arrangement shown, as one example,lower walls 54 connect at their lower end to the upper end of interiorwall 26.

As grain moves through wet hold section 32 from loading system 30 andinto grain columns 22, grain is directed by the angling of the upperside walls 78 and upper end walls 80 on the upper side, and the lowerwalls 54 on the lower side. The volumetric holding capacity of wet holdsection 32 ensures that an adequate buffer of wet grain is on hand atall times to ensure the grain columns 22 are always filled whileaccommodating loading variability during use. In this way, wet holdsection 32 stages grain for drying in grain columns 22 as well asdirects grain into grain columns 22 under the force of gravity. To beclear, in a manner of speaking, grain columns 22 begin in wet holdsection 32 between upper side walls 78 and lower walls 54.

Mixed-Flow Heating Section:

In the arrangement shown, as one example, mixed-flow grain dryer withcross-flow vacuum cool heat recovery system 10 includes a mixed-flowheating section 34. Mixed-flow heating section 34 is formed of anysuitable size, shape and design and is configured to facilitate dryingof grain in grain columns 22 in a gentle and efficient manner.

In the arrangement shown, as one example mixed-flow heating section 34extends vertically from its upper end 84, at the lower end of wet holdsection 32, to its lower end 86, at the upper end of tempering section36. Mixed-flow heating section 34 is defined at its outward sides by theexterior surface of exterior walls 24. Mixed-flow heating section 34 isdefined at its outward ends by the exterior surface of end walls 52.

In the arrangement shown, as one example, grain columns 22 extendthrough mixed-flow heating section 34 from its upper end 84 to its lowerend 86. More specifically, in the arrangement shown, as one example,grain columns 22 of heating section 34 have a generally consistent widthand shape from upper end 84 to lower end 86. That is, grain columns 22of heating section 34 are defined at their outward sides by the interiorsurface of exterior walls 24 and at their inward sides by the interiorsurface of interior walls 26, wherein exterior walls 24 and interiorwalls 26 extend in approximate parallel spaced relationship to oneanother from upper end 84 to lower end 86. Similarly, grain columns 22of heating section 34 are defined at their outward ends by the interiorsurface end walls 52, wherein end walls 52 extend in approximateperpendicular relationship to exterior walls 24 and interior walls fromupper end 84 to lower end 86. In this way, grain columns 22 of heatingsection 34 are generally square or rectangular in shape.

In the arrangement shown, as one example, the interior ends of opposinggrain columns 22 of mixed-flow heating section 34 are separated from oneanother by heat plenum 62 of plenum 28. To provide enhanced strength andrigidity, a plurality of structural members 66 extend across heat plenum62 in a crossing pattern thereby connecting one grain column 22 to theother grain column 22. Heat plenum 62 receives heated and pressurizedair from air handling system 42. This heated and pressurized airreceived by heat plenum 62 passes through a series of inlet ducts 88,through the grain in grain column 22, and through a series of exhaustducts 90.

Inlet ducts 88 and exhaust ducts 90 may be formed of any suitable size,shape and design and are configured to allow the flow of heated airthrough the grain in grain column 22 of heating section 34 so as tofacilitate gentle heating and drying of the grain. In the arrangementshown, as one example, when viewed from a side 16, inlet ducts 88 andexhaust ducts 90 are generally triangular shaped members having a pairof opposing walls 92 that connect to one another at their upper end at apeak 94 and extend outward and downward from the peak 94 at an anglebefore terminating their lower ends. The lower ends of inlet ducts 88and exhaust ducts 90 are open, thereby allowing for the free flow of airinto the inlet ducts 88 and exhaust ducts 90 from their open lower end.

In one arrangement, the lower end of inlet ducts 88 and exhaust ducts 90are completely open. This configuration of having an open lower end ofinlet ducts 88 and exhaust ducts 90 is acceptable in many applicationsdue to the manner in which grain moves through grain columns 22 underthe force of gravity which prevents the grain from escaping through theopen lower end of inlet ducts 88 and exhaust ducts 90. In anotherarrangement the lower end of inlet ducts 88 and exhaust ducts 90 arecovered by a screen, a perforated sheet or another component that allowsair flow there through while preventing animals and birds from enteringthe grain column 22 and/or heat plenum 62 and/or preventing grain fromescaping inlet ducts 88 and exhaust ducts 90.

Inlet ducts 88 and exhaust ducts 90 extend a length between opposingends. In the arrangement shown, as on example, inlet ducts 88 andexhaust ducts 90 extend approximately the width of grain column 22 ofheating section 34. In this way, the interior end of inlet ducts 88 andexhaust ducts 90 is positioned at, in or adjacent to the interior wall26 of grain columns 22. Similarly, the exterior end of inlet ducts 88and exhaust ducts 90 is positioned at, in or adjacent to the exteriorwall 24 of grain columns 22. In the arrangement shown, as one example,the interior end of inlet ducts 88 and exhaust ducts 90 is connected tothe interior wall 26 of grain columns 22, and the exterior end of inletducts 88 and exhaust ducts 90 is connected to exterior wall 24. In thisway, the interior end and exterior end of inlet ducts 88 and exhaustducts 90 are rigidly supported within grain column 22.

In the arrangement shown, as one example, inlet ducts 88 and exhaustducts 90 are arranged in rows or tiers 96 that extend from the forwardend 18 of heating section 34 to the rearward end 20 of heating section34 with each inlet duct 88 or exhaust duct 90 spaced from the inlet duct88 or exhaust duct 90 on either side. In the arrangement shown, as oneexample, inlet ducts 88 are arranged in tiers 96, and exhaust ducts 90are arranged in tiers 96. In the arrangement shown, as one example,heating section 34 is formed of alternating tiers 96 of inlet ducts 88and tiers 96 of exhaust ducts 90. Or, said another way, each tier 96includes only inlet ducts 88 or exhaust ducts 90, and each tier 96 ofinlet ducts 88 has a tier 96 of exhaust ducts 90 above as well as belowthe tier 96 of inlet ducts 88, and similarly, each tier 96 of exhaustducts 90 has a tier 96 of inlet ducts 88 above as well as below the tier96 of exhaust ducts 90.

However, any other configuration or arrangement of inlet ducts 88 andexhaust ducts 90 is hereby contemplated for use such as tiers 96 havingan alternating pattern of an inlet duct 88 next to an exhaust duct 90 orany other arrangement or configuration.

Also, in the arrangement shown, as one example, the tiers 96 of inletducts 88 and exhaust ducts 90 are laterally offset from one another.That is, the inlet ducts 88 are laterally offset from the exhaust ducts90 of the adjacent tiers 96. Or, said another way, inlet ducts 88 of onetier 96 are not positioned directly above or below the exhaust ducts 90of adjacent tiers 96. Instead, inlet ducts 88 of one tier 96 arepositioned between the exhaust ducts 90 of vertically adjacent tiers 96,and similarly exhaust ducts 90 of one tier 96 are positioned between theinlet ducts 88 of adjacent tiers 96. This lateral offsetting ofvertically adjacent inlet ducts 88 and exhaust ducts 90 helps to causemixing air flow through the grain in grain column 22. This lateraloffsetting of vertically adjacent inlet ducts 88 and exhaust ducts 90helps to cause the grain to move within grain column 22 as it travelsvertically through the grain column 22 by engaging the offset inletducts 88 and exhaust ducts 90. This mixing of the airflow as well asmixing of the grain in heat section 34 facilitates consistent and gentledrying of the grain.

In the arrangement shown, as one example, inlet ducts 88 have an openinterior end that connects to heat plenum 62. Or, said another way, theinterior end of inlet ducts 88 connect to an opening in the interiorwall 26. In this way, the open interior end of inlet ducts 88 allow airflow from the pressurized heat plenum 62 and into the inlet ducts 88.Then, due to the open lower end of inlet ducts 88 air passes through theopen lower end of inlet ducts 88 and into the grain of grain column 22.

Similarly, in the arrangement shown, as one example, exhaust ducts 90have an open exterior end that connects to the atmosphere or ventsoutside of the system 10. Or, said another way, the exterior end ofexhaust ducts 90 connect to an opening in the exterior wall 24. In thisway, the open lower end of exhaust ducts 90 allows pressurized air flowfrom the grain column 22 to enter into the exhaust ducts 90. Then, dueto the open exterior end of exhaust ducts 90 air passes through the openexterior end of exhaust ducts 90 and into the atmosphere therebycarrying with it moisture from the heated grain.

In the arrangement shown, as one example, heating section 34 is formedby a plurality of panels 98 that form exterior wall 24 as well asinterior wall 26. Panels 98 may also be used for end wall 52 as well asother components of the system 10. Each panel 98 includes a plurality ofinlet ducts 88 and a plurality of exhaust ducts 90. In the arrangementshown, as one example, each panel 98 includes a tier 96 of exhaust ducts90 at the lower side of the panel 98 and a tier 96 of inlet ducts 88 atthe upper side of the panel 98. However, the opposite arrangement ishereby contemplated for use. These panels 98 are then stacked on top ofone another as well as connected to laterally adjacent and verticallyadjacent panels 98 thereby forming the grain columns 22 of heat section34 in a quick and easy and secure manner.

Also, in the arrangement shown, as one example, one tier 96 of exhaustducts 90 are positioned adjacent the lower end of wet hold section 32.Due to the inward sloping of upper side walls 78 of wet hold section 32,the outer end of exhaust ducts 90 in wet hold section 32 protrude upwardout of the exterior sides of upper side walls 78. In the arrangementshown, as one example, mixed-flow heating section 34 is formed of panels98 stacked six high and four across, each panel 98 having exhaust ducts90 positioned at their lower end and inlet ducts 88 positioned at theirupper end.

In the arrangement shown, the exterior walls 24, interior walls 26 andend walls 52 of grain column 22 of mixed-flow heating section 34 aresolid thereby preventing air flow through the exterior walls 24,interior walls 26 and end walls 52 of grain column 22. This is otherthan the openings in interior walls 26 that inlet ducts 88 connect toand the openings in exterior walls 24 that exterior ducts 90 connect to.

In the arrangement show, as one example, the lower end of mixed-flowheating section 34 connects to the upper end of tempering section 36.The lower end of mixed-flow heating section 34 is enclosed by the uppersurface of divider 60. In the arrangement shown, a tier of exhaust ducts90 are positioned a distance above the lower end 86 of heating section34.

Tempering Section:

In the arrangement shown, as one example, mixed-flow grain dryer withcross-flow vacuum cool heat recovery system 10 includes a temperingsection 36. Tempering section 36 is formed of any suitable size, shapeand design and is configured to facilitate the transition of grain fromthe mixed-flow heating section 34 to the cross-flow cooling section 38.

In the arrangement shown, as one example tempering section 36 extendsvertically from its upper end, at the lower end 86 of mixed-flow heatingsection 34, to its lower end 100, at the upper end of unloading system40. Tempering section 36 is defined at its outward sides by the exteriorsurface of exterior walls 24. Tempering section 36 is defined at itsoutward ends by the exterior surface of end walls 52.

In the arrangement shown, as one example, grain columns 22 extendthrough tempering section 36 from its upper end to its lower end. In thearrangement shown, as one example, grain columns 22 of tempering section36 vary in width from their upper end to their lower end. That is, thewidth of the grain column 22 at the upper end of tempering section 36 iswider than the width of the grain column 22 at the lower end oftempering section 36. This is because, due to the operational nature ofthe mixed-flow heating section 34, the grain columns 22 are wider in themixed-flow heating section 34 as compared to the grain columns 22 of thecross-flow cooling section 38. This difference in the width of graincolumns 22 between the mixed-flow heating section 34 and the cross-flowcooling section 38 causes the grain to remain in the grain column 22 ofthe mixed-flow heating section 34 longer than the grain remains in thegrain column 22 of the cross-flow cooling section 38. Or, said anotherway, the grain moves through the narrower grain columns 22 of thecross-flow cooling section 38 faster than the grain moves through thewider grain columns 22 of the mixed-flow heating section 34. The speedat which the grain moves the grain columns 22 of the mixed-flow heatingsection 34 the cross-flow cooling section 38 is also varied by theheight of these portions of the grain columns 22 as well as the speed atwhich the unloading system 40 operates. In this way, optimal operationalperformance may be achieved by varying the height of the variousportions of the grain columns 22, the width of the various portions ofthe grain columns 22, the unload speed of the unloading system 40, aswell as other features such as the temperature of the air blown into theheat plenum 62, the pressure applied by fan system 44 to both the coolplenum 64 and heat plenum 62, the size, shape, position, density andconfiguration of the inlet ducts 88 and exhaust ducts 90 and the size,shape, density and configuration of the perforations in the exteriorwall 24 and interior wall 26 of cross-flow cooling section 38. theheight of the sections of the grain columns 22 between the mixed-flowheating section 34 and the cross-flow cooling section 38 causes thegrain to remain in the grain column 22 of the mixed-flow heating section34 longer than the grain remains in the grain column 22 of thecross-flow cooling section 38.

In the arrangement shown, as one example, grain columns 22 of temperingsection 36 are defined at their outward sides by the interior surface ofexterior walls 24 and at their inward sides by the interior surface ofinterior walls 26. Similarly, grain columns 22 of tempering section 36are defined at their outward ends by the interior surface end walls 52.

As mentioned, tempering section 36 narrows the width of grain column 22as it extends downward from mixed-flow heating section 34 to cross-flowcooling section 38. In the arrangement shown, as one example, theexterior wall 24 of tempering section 36 extends slightly inward at anangle from its upper end (at the lower end 86 of mixed-flow heatingsection 34) to midpoint 102 positioned approximately two thirds of theway down the tempering section 36 and about one third of the way abovethe lower end 100 of tempering section 36. In the arrangement shown, asone example, the exterior wall 24 of tempering section 36 extendsapproximately vertically between midpoint 102 and the lower end 100 oftempering section 36. Similarly, In the arrangement shown, as oneexample, the interior wall 26 of tempering section 36 extends inward atan angle from its upper end (at the lower end 86 of mixed-flow heatingsection 34) to midpoint 102 positioned approximately two thirds of theway down the tempering section 36 and about one third of the way abovethe lower end 100 of tempering section 36. In the arrangement shown, asone example, the interior wall 26 of tempering section 36 extendsapproximately vertically between midpoint 102 and the lower end 100 oftempering section 36. In the arrangement shown, as one example, theangle of interior wall 26 is substantially greater than the angle ofexterior wall 24. However, any other configuration of is herebycontemplated for use as tempering section 36.

In the arrangement shown, as one example, exterior wall 24 and interiorwall 26 of tempering section 36 are solid from their upper end to theirlower end. As such, air flow is prevented through exterior wall 24 andinterior wall 26 of tempering section 36 which substantially reduces,prevents and/or wholly stops air flow through the grain column 22 intempering section 36. This is important in that the tempering section 36separates the mixed-flow heating section 34 from the cross-flow coolingsection 38 and the mixed-flow heating section 34 operates by air beingforced outward through the grain column 22 while the cross-flow coolingsection 38 operates by air being pulled inward through the grain column22. By having the exterior wall 24 and interior wall 26 of temperingsection 36 be of requisite height as well as be solid, this reduces,prevents or stops the bleeding of air flow from one of the cross-flowcooling section 38 and the mixed-flow heating section 34 to the other ofthe cross-flow cooling section 38 and the mixed-flow heating section 34.In this way, the solid exterior wall 24 and interior wall 26 oftempering section 36 serves to separate the reverse air flows ofmixed-flow heating section 34 from the cross-flow cooling section 38.

In the arrangement shown, as one example, the upper end of temperingsection 36 approximately aligns with the plane formed by divider 60which separates heat plenum 62 from cool plenum 64. The presence ofdivider 60 at the upper end of tempering section 36 further helps tolimit the bleeding of air flow from one of the cross-flow coolingsection 38 and the mixed-flow heating section 34 to the other of thecross-flow cooling section 38 and the mixed-flow heating section 34.

In the arrangement shown, as one example a baffle 104 is positionedwithin the grain column 22 of tempering section 36. Baffle 104 is formedof any suitable size, shape and design and is configured to help directgrain flow from the grain column 22 of mixed-flow heating section 34 tothe grain column 22 of the cross-flow cooling section 38 in an even andconsistent manner such that grain flows evenly across the width of thegrain column 22 of mixed-flow heating section 34 so as to facilitateeven heating and drying. In one arrangement baffle 104 is useful inevening the flow of grain from grain column 22 of mixed-flow heatingsection 34 due to the narrowing of the grain column 22 in temperingsection 36 and/or the varying angles of exterior wall 24 and interiorwall 26 of tempering section 36.

In the arrangement shown, as one example, a single baffle 104 ispositioned in the grain column 22 of tempering section 36, however anynumber of baffles 104 are hereby contemplated for use such as none, two,three, four or more. In the arrangement shown, as one example, baffle104 is a generally flat and straight planar member that extends thelength of tempering section 36 from end wall 52 to end wall 52, howeverany other size shape and configuration is hereby contemplated for use.In the arrangement shown, as one example, the upper end of baffle 104 ispositioned in approximate alignment with the upper end of temperingsection 36 and the lower end of baffle 104 terminates in approximatealignment with the midpoint 102, which coincides with the grain columnresuming vertically extending exterior walls 24 and interior walls 26.In this way, baffle 104 evenly transitions the flow of grain from thevertically extending straight exterior walls 24 and interior walls 26 ofmixed-flow heating section 34 to the vertically extending straightexterior walls 24 and interior walls 26 of cross-flow cooling section38. As baffle 104 is itself a solid member, baffle 104 also serves toreduce cross-flow air movement within grain column 22.

If it were not for divider and the solid exterior walls 24 and interiorwalls 26 of tempering section 36, the vacuum air pressure of cross-flowcooling section 38 would draw air in from the mixed-flow heating section34. By separating cross-flow cooling section 38 from the mixed-flowheating section 34 by the length of the solid exterior walls 24 andinterior walls 26 of tempering section 36 this reduces or preventscross-contamination of air flow between cross-flow cooling section 38and mixed-flow heating section 34.

The lower end 100 of tempering section 36 connects to the upper end ofcross-flow cooling section 38.

In one arrangement, the width of grain column 22 in the mixed-flowheating section 34 is approximately thirty inches wide, whereas thewidth of the grain column 22 in the cross-flow cooling section 38 isapproximately fourteen inches wide. As such, in this arrangement, as oneexample, the width of the grain column 22 in the cross-flow coolingsection 38 is less than half the width of the grain column 22 in themixed-flow heating section 34. Any other configuration or dimensions arehereby contemplated for use.

Cross-Flow Cooling Section:

In the arrangement shown, as one example, mixed-flow grain dryer withcross-flow vacuum cool heat recovery system 10 includes a cross-flowcooling section 38. Cross-flow cooling section 38 is formed of anysuitable size, shape and design and is configured to facilitate coolingof grain in grain columns 22 as well as facilitating heat recovery toimprove energy efficiency of the system 10.

In the arrangement shown, as one example cross-flow cooling section 38extends vertically from its upper end, at the lower end 100 of temperingsection 36, to its lower end 106, at the upper end of unloading system40. Cross-flow cooling section 38 is defined at its outward sides by theexterior surface of exterior walls 24. Cross-flow cooling section 38 isdefined at its outward ends by the exterior surface of end walls 52.

In the arrangement shown, as one example, grain columns 22 extendthrough cross-flow cooling section 38 from its upper end to its lowerend 106. More specifically, in the arrangement shown, as one example,grain columns 22 of cross-flow cooling section 38 have a generallyconsistent width and shape from the lower end 100 of tempering section36 to a transition point 108 midway between the upper end of cross-flowcooling section 38 and the lower end 106 cross-flow cooling section 38.That is, grain columns 22 of cross-flow cooling section 38 are definedat their outward sides by the interior surface of exterior walls 24 andat their inward sides by the interior surface of interior walls 26,wherein exterior walls 24 and interior walls 26 extend in approximateparallel spaced relationship to one another from upper end of cross-flowcooling section 38 to lower end 106 of cross-flow cooling section 38.Similarly, grain columns 22 of cross-flow cooling section 38 are definedat their outward ends by the interior surface end walls 52. In this way,grain columns 22 of cross-flow cooling section 38 above transition point108 are generally square or rectangular in shape and extend vertically.

In the arrangement shown, as one example, at transition point 108, graincolumns 22 transition from vertical extension to an angled inwardextension toward the generally centrally positioned unloading system 40.More specifically, the exterior walls 24 and interior walls 26 angleinward at transition point 108. Notably, the width of grain columns 22remain constant above and below transition point 108 and the transitionpoint 108 in interior wall 26 is positioned slightly above thetransition point 108 in exterior wall 24, so as to maintain a consistentwidth of grain column 22 above and below transition point 108.

In the arrangement shown, as one example, exterior wall 24 and interiorwall 26 of cross-flow cooling section 38 facilitate airflow through thegrain columns 22. In one arrangement, exterior wall 24 and interior wall26 of cross-flow cooling section 38 are formed of perforated sheets ofmaterial, however any other configuration of a barrier that prevents thepassage of grain there through while allowing for air flow there throughis hereby contemplated for use.

The lower end 106 of cross-flow cooling section 38 connects to and feedsgrain to the upper end of unloading system 40.

In use, air handling system 42 is fluidly connected to the hollowinterior of cool plenum 64. Air handling system 42 applies a vacuum tocool plenum 64 thereby sucking or pulling air out of cool plenum 64.This vacuum applied to cool plenum 64 causes air to be drawn through theair-permeable exterior wall 24 of cross-flow cooling section 38, the airis then drawn through the grain in the grain column 22 of cross-flowcooling section 38, the air is then drawn through the air-permeableinterior wall 26 and into the cool plenum 64. Air handling system 42,using fan system 44 then pulls air out of the cool plenum 64 and blowsit under pressure into heat plenum 62 along with heat added by heatingsystem 46.

As ambient air is drawn through the heated grain in grain column 22 ofcross-flow cooling section 38, the ambient air cools the grain and isitself warmed. This air flow also helps to carry away moisture from theheated grain thereby further drying the grain. The result is that theair that is fed into the air handling system 42 is warmed therebyharnessing the principles of heat conservation, and recycling heat. Thismeans that the air that is blown into the heat plenum 62 must be warmedto a lesser degree than it would otherwise be if ambient air was used.As the air blown into heat plenum 62 needs to be heated to a lesserdegree to achieve the desired temperature due to the conservation ofheat and recycling of heat, lets energy is used to dry the grain.Another benefit is that the temperature of the grain that is dischargedfrom the cross-flow cooling section 38 is cooler than it would otherwisebe if it were not passed through the cross-flow cooling section 38.Cooling the grain before it is stored improves the stability of thegrain in long term storage and requires less handling precautions.

Another substantial benefit of the cross-flow cooling section 38 is thatangles inward at its lower end thereby facilitating unloading of thegrain at a single unload point, which is unloading system 40.

Unloading System:

In the arrangement shown, as one example, mixed-flow grain dryer withcross-flow vacuum cool heat recovery system 10 includes an unloadingsystem 40. Unloading system 40 is formed of any suitable size, shape anddesign and is configured to facilitate unloading of dry grain fromsystem 10.

Any form of a grain unloading system is hereby contemplated for use asunloading system 40. In the arrangement shown, as one example, unloadingsystem 40 is an auger system that receives grain from the ends of eachgrain column 22. A shaft 70 with fighting 71 extends across the lowerend of system 10. The shaft 70 with fighting 71 is connected to a motor72 (not shown) by a pulley and belt system (also not shown) and isconfigured to rotate the shaft 70 with fighting 71. Unloading system 40facilitates the discharge of grain at a single discharge point 110.

In the arrangement shown, as one example, the exterior walls 24 angleinward from the lower end 106 of cross-flow cooling section 38 to thepoint where they connect to one another just below the center ofunloading system 40, or more specifically the center of shaft 70 withfighting 71. Similarly, in the arrangement shown, as one example, theinterior walls 26 angle inward from the lower end 106 of cross-flowcooling section 38 to the point where they connect to one another justabove the center of unloading system 40, or more specifically the centerof shaft 70 with flighting 71. In this way, the adjacent grain columns22 converge with one another at unloading system 40.

In the arrangement shown, as one example, a baffle 112 is positioned ingrain column 22 a distance upstream of shaft 70 with flighting 71.Baffle 112 is connected at its upward end to the interior surface ofinterior wall 26 and angles downward therefrom, across grain column 22,before terminating at a free end adjacent metering roll 114. Baffle 112serves to direct grain from grain column 22 to metering roll 114 in sucha way that the grain is evenly removed from grain column 22.

Metering roll 114 is formed of any suitable size, shape and design andis configured to control the speed at which grain is metered out of thelower end of grain column 22 and into the unloading system 40 fordischarge out of the system 10. In the arrangement shown, as oneexample, metering rolls 114 include a shaft 116 having flights 118. Asthe metering rolls 114 rotate, a quantity of grain is discharged to beunloaded. As such, the faster the metering rolls 114 rotate the fasterthe grain is discharged. The faster the metering rolls 114 rotate, thefaster the grain moves through grain columns 22. In the arrangementshown, baffles 112 and metering rolls 114 extend the forward to backlength of system 10 from front end wall 52 to rear end wall 52.

In the arrangement shown, as one example, a single baffle 112 and asingle metering roll 114 is shown the grain column 22 on each side ofunloading system 40. However, it is hereby contemplated for use to usetwo or more baffles and/or metering rolls 114, which can provideoperational advantages, such as independent control and increaseddischarge rates, among other advantages.

In operation, when grain in grain columns 22 reach the unloading system40 the grain is directed by baffle 112 towards metering roll 114. Theshape, position and configuration of baffle 112 serves to ensure thatgrain is evenly moved from grain column 22. As metering roll 114rotates, as each flight 118 rotates, an amount of grain is moved passedbaffle 112 and metering roll 114. This grain, slides under the force ofgravity along the interior lower surface of exterior wall 24 until itreaches the shaft 70 with fighting 71. As the shaft 70 with fighting 71rotates, the grain is moved along the length of system 10 to a dischargepoint 110 at which point the grain exits system 10.

While in the arrangement shown, only a single auger, or shaft 70 withflighting 71 is used, it is hereby contemplated that multiple augers ormultiple shafts 70 with fighting 71 are used in unloading system 40.Alternatively, a belt, a conveyor, a paddle sweep and/or a drag chainsystem is hereby contemplated for use as unloading system 40. Any otherstructure or configuration of a system for loading grain is herebycontemplated for use as unloading system 40.

Air Handling System:

In the arrangement shown, as one example, mixed-flow grain dryer withcross-flow vacuum cool heat recovery system 10 includes an air handlingsystem 42. Air handling system 42 is formed of any suitable size, shapeand design and is configured to facilitate air flow through the system10 using fan system 44 as well as facilitating heating of that air flowusing heating system 46.

In the arrangement shown, as one example, air handling system 42 isconnected to the forward end wall 52 of system 10. More specifically,air handling system 42 is connected to both the cool plenum 64 as wellas the heat plenum 62.

In the arrangement shown, as one example, air handling system 42includes a fan system 44. Fan system 44 is formed of any suitable sizeshape and design and is configured to provide air flow through thesystem 10. Fan system 44 may be formed of a single fan, or a pluralityof fans or any other device that facilitates air flow.

In the arrangement shown, fan system 44 is fluidly connected to coolplenum 64 at its input end. In this way, when in operation, fan system44 applies a vacuum to cool plenum 64 which has the effect of pulling ordrawing air into the cool plenum 64 through the air permeable exteriorwall 24 of cross-flow cooling section 38, through the grain held in thegrain column 22 of cross-flow cooling section 38, and through theinterior wall 26 of cross-flow cooling section 38 and into cool plenum64.

In the arrangement shown, fan system 44 is fluidly connected to heatplenum 62 at its output end. In this way, when in operation, fan system44 applies pressurized air flow to heat plenum 62 which has the effectof forcing air into heat plenum 62, through the open interior ends ofinlet ducts 88, out the open lower ends of inlet ducts 88 and into thegrain column 22, through the grain column 22, into the open lower endsof exhaust ducts 90, and out the open exterior end of the exhaust ducts90 where it is vented to the environment.

In the arrangement shown, as one example, air handling system 42includes a heating system 46. Heating system 46 is formed of anysuitable size shape and design and is configured to provide heat to heatthe air flow through the system 10. In one configuration, heating system42 is placed at the output end of fan system 44 and is formed of one ormore burners. When in operation, heating system 46 heats the air flowthat is blown into heat plenum 62 of mixed-flow heating section 34.

In the arrangement shown, as one example, air handling system 42includes louvers 48. Louvers 48 are formed of any suitable size, shapeand design and are configured to control the amount of air that ispulled through cool plenum 64 as compared to the amount of air that ispulled from the surrounding environment. As louvers 48 are closed, moreair is drawn through the cool plenum 64, which means more air is drawnthrough the grain in grain column 22 of the cross-flow cooling section38 thereby cooling the grain to a greater amount and recycling moreheat. As louvers 48 are opened, more air is drawn from the surroundingenvironment, which means less air is drawn through the grain in graincolumn 22 of the cross-flow cooling section 38 thereby cooling the grainto a lesser amount and recycling less heat.

In the arrangement shown, as one example, air handling system 42 isfluidly connected to the end wall 52 by a duct system 120 that forms anair passage way from cool plenum 64 to the input end of air handlingsystem 42 as well as forms an air passage way from the output end of airhandling system 42 to the heat plenum 62. Through the air passage waysformed by duct system 120 air is passed from cool plenum 64 to airhandling system 42 to heat plenum 62.

Also, in the arrangement shown, air handling system 42 has a housing 122that surrounds the exterior of air handling system 42. This housing 122serves to prevent and/or control the air flow into and out of the airhandling system 42. In the arrangement shown, as one example, louvers 48selectively cover openings in this housing 122.

Support System:

In the arrangement shown, as one example, mixed-flow grain dryer withcross-flow vacuum cool heat recovery system 10 includes a support system50. Support system 50 is formed of any suitable size, shape and designand is configured to provide strength and rigid support for mixed-flowgrain dryer with cross-flow vacuum cool heat recovery system 10.

In the arrangement shown, as one example, mixed-flow grain dryer withcross-flow vacuum cool heat recovery system 10 has a single pointunloading system 40. This provides many advantages as the grain isunloaded at a single point by a single mechanical device (unloadingsystem 40) which reduces mechanical complexity of the system 10 in someways and eliminates moving parts. While having a single point unloadprovides some benefits, it also provides some challenges. Namely, due tothe inwardly angling exterior walls 24 that connect to unloading system40, the lower end of system 10 is not well suited to sit upon the groundor a platform. Instead, due to the configuration of the lower end of thesystem 10, a support system 50 is needed to raise the lower end of thesystem 10 above the ground or platform upon which it rests and/orprovide additional stability to the system 10.

In the arrangement shown, as one example, support system 50 is formed ofa plurality of horizontal supports 124 and a plurality of verticalsupports 126. Horizontal supports 124 and vertical supports 126 areformed of any suitable size, shape and design and extend between andconnect to the platform upon which system 10 sits and/or structuralcomponents of the system 10, and/or horizontal supports 124 and verticalsupports 126 connect to one another. In the arrangement shown, as oneexample the plurality of horizontal supports 124 and plurality ofvertical supports 126 raise the main body of system 10 above the groundor platform that system 10 sits upon as well as provides a strong andstable base for system 10.

In Operation:

In operation, wet grain is supplied to the input 68 of loading system30. The as the motor 72 operates this causes the shaft 70 with fighting71 to rotate which causes the grain to evenly move across the upper endof the wet hold section 32. When the wet grain is added to the wet holdsection 32 the grain travels down under the force of gravity betweenexterior wall 24 and interior wall 26. The grain is separated into apair of grain columns 22 which exist on each side of a plenum 28. As thegrain exits the lower end of the wet hold section 32 the grain entersthe upper end of the mixed-flow heating section 34.

As the grain travels down the mixed-flow heating section 34 the graintravels downward within the grain column 22 between the exterior wall 24and interior wall 26 and between end walls 52. As the grain travelsdownward within the grain column 22 of mixed-flow heating section 34 thegrain encounters the triangular shaped inlet ducts 88 and exhaust ducts90 that extend across the grain columns 22. As the grain encounters thetriangular shaped inlet ducts 88 and exhaust ducts 90 the grain isdirected to one side or the other due to the triangular shaped inletducts 88 and exhaust ducts 90. It is important to note that due to theoff-set position of vertically adjacent inlet ducts 88 and exhaust ducts90, the grain is moved laterally within the grain column 22. Thislateral movement, as the grain moves vertically, has a mixing effect onthe grain, which facilitates gentle and even heating of the grain.

As the grain passes through the grain column 22 of the mixed-flowheating section 34, heated air is blown by the air handling system 42into the heat plenum 62. This heated pressurized air flow to heat plenum62 is forced through the open interior ends of inlet ducts 88 thatconnect with interior wall 26. This heated pressurized air flow is thenforced along the length of inlet ducts 88 until it passes out the openlower end of inlet ducts 88 and into the grain of grain column 22. Thisheated pressurized air flow passes through the grain in the grain column22 thereby heating and drying the grain. This heated pressurized airflow finds its way into the open lower end of exhaust ducts 90. Thisheated pressurized air is then forced along the length of exhaust ducts90 until it passes out the open exterior end of exhaust ducts 90 atwhich point it is vented to the atmosphere.

As the grain travels downward and passes the lower end of mixed-flowheating section 34 the grain enters the tempering section 36. As thegrain enters the tempering section 36 the grain engages the inwardangling exterior wall 24 and interior wall 26 which narrows the width ofthe grain column 22 from the wider mixed-flow heating section 34 to thenarrower cross-flow cooling section 38. In this transition, the grainengages baffle 104 which ensures the grain is evenly removed from themixed-flow heating section 34. Due to the interior wall 26 and exteriorwall 24 of tempering section 36 being solid and air impermeable, littleor no air flows through the grain in grain column of tempering section36.

As the grain travels downward and passes the lower end of temperingsection 36 the grain enters the cross-flow cooling section 38. As thegrain travels down the grain column in the cross-flow cooling section 38air is pulled through the air permeable exterior wall 24, through thegrain in the grain column 22 thereby cooling and further drying thegrain, and through the air permeable interior wall 26, and into the coolplenum 64. This warmed air is then recycled by air handling system 42 upto the heat plenum 62 of the mixed-flow heating section 34 withsupplemental heat added by heating system 46 and so the cycle isrepeated.

As the grain exits the lower end of the cross-flow cooling section 38the grain enters the unloading system 40. As the grain travels down thegrain column 22 of the unloading system 40 the grain engages and isdirected by the baffle 112 toward metering roll 114. As the meteringroll 114 rotates grain is dispensed to the auger system having a shaft70 and fighting 71. As the shaft 70 with flighting 71 rotates the grainis moved along the length of the system 10 until it passes out thedischarge point 110.

In this way, grain is heated and dried in an efficient and gentle mannerusing mixed-flow heating section 34, tempering section 36 and cross-flowcooling section 38 of mixed-flow grain dryer with cross-flow vacuum coolheat recovery system 10.

Central Controller:

In the arrangement shown, as one example, mixed-flow grain dryer withcross-flow vacuum cool heat recovery system 10 includes a centralcontroller that controls operation of the mixed-flow grain dryer withcross-flow vacuum cool heat recovery system 10, or more specificallycontrols operation of the loading system 30, the unloading system 40,the air handling system 42 including fan system 44, heating system 46and louvers 48, and any other electrical and/or controllable componentof the system 10.

Second Mixed-Flow Heating Section:

In one arrangement, a second mixed-flow heating section 34 with its ownair handling system 42 is positioned on top of the first mixed-flowheating section 34. In this arrangement, the heat plenum 62 of the firstmixed-flow heating section 34 and the heat plenum 62 of the secondmixed-flow heating section 34 are separated by a divider 60. For allintents and purposes the second mixed-flow heating section 34 and airhandling system 42 operate similarly if not identically to the firstmixed-flow heating section 34 and air handling system 42 describedherein with the biggest difference being that there is no heat recoveryassociated with the second air handling system 42. That is, the secondair handling system 42 simply blows heated air into the heat plenum 62of the second mixed-flow heating section 34. The addition of a secondmixed-flow heating section 34 increases capacity of the system 10.

It is hereby contemplated that any number of additional mixed-flowheating sections 34 with their own air handling systems 42 may bestacked onto the system 10 presented herein to add capacity to thesystem 10 such as two, three, four, five, six or more additionalmixed-flow heating sections 34 with their own air handling systems 42.

Bridge Reducing Mixed Flow Grain Dryer Arrangement:

Overview: Mixed flow grain dryers, such as the mixed flow grain dryersystem depicted as reference numeral 10 herein, have many benefits. Onesubstantial benefit of mixed flow grain dryer system 10 is that due tothe manner in which heated air flows from the heat plenum 62, throughthe interior wall 26 through the open interior end of the inlet ducts88, out of the open bottom end of the inlet ducts 88, through the grainin the grain column 22, and into the open bottom end of the exhaustducts 90 and out the exterior wall 24 through the open exterior end ofthe exhaust ducts 90, this process is very gentle on the grain. Anothersubstantial benefit of mixed flow grain dryer system 10 is that due tothe offset nature of the plurality of inlet ducts 88 and exhaust ducts90 that extend across the grain column 22, as the grain moves verticallydownward through the grain column 22 the grain encounters and movesaround the plurality of inlet ducts 88 and exhaust ducts 90 which causesmixing of the grain thereby causing even heating and drying.

While mixed flow grain dryers (e.g., system 10) have many benefits, ithas been observed that mixed flow grain dryers 10 may suffer fromplugging or bridging in some situations. Plugging is a serious problembecause plugged grain reduces the throughput of the grain dryer 10.Plugging is also a serious problem because the plugged grain can getoverly dried and once dried can catch fire thereby causing damage to thegrain dryer 10.

It has been discovered that, in some instances, mixed flow grain dryersystem 10 suffer from bridging of grain or grain clumps between endwalls 52 and the outward-most positioned inlet ducts 88 and/or exhaustducts 90. An example of this arrangement is depicted in FIG. 19. In FIG.19 bridged grain 200 is captured between the outward facing angled outerwall 92 of outer most ducts 202 and the vertically extending interiorsurface of end wall 52. That is, in this arrangement, bridged grain 200clumps up and gets caught between the outwardly extending and downwardlyangled wall 92 of the outward-most inlet ducts 88 and/or exhaust ducts90 and the vertically extending interior surface of end wall 52. This isbecause, in this area the grain is funneled through an ever-narrowingspace between ducts 88, 90 and end wall 52. In contrast, in thearrangement shown, as one example, the distance between the lower end ofall of the other inlet ducts 88 and/or exhaust ducts 90 is approximatelytwice the distance between the lower end of the outward-most-positionedinlet duct 88 and/or exhaust duct 90 and end wall 52.

Bridged grain 200 can occur for any number of reasons such as grainclumps, particularly moist grain, sticky grain, dirty grain, largegrain, roughness on the walls 92 of ducts 88, 90, roughness on the endwall 52, foreign objects in the grain, or any combination of thesefactors, among countless other reasons. When bridged grain 200 occurs,this stops the flow of grain at the outward sides of mixed flow graindryer 10. When bridged grain 200 occurs, this can require manual removalof the bridged grain 200 or other maintenance to remove the bridgedgrain 200 and/or prevent bridged grain 200 from occurring again. In someinstances, when bridging occurs, the bridged grain is heated longer thanintended and may catch fire, which can damage or destroy the grain dryer10 and/or cause injury or death, loss of drying capacity, loss of grain,among other problems.

Mixed Flow Grain Dryer System 194:

With reference to FIGS. 20-25, an alternative mixed flow grain dryersystem 194 arrangement is presented that prevents grain from bridging.This alternative arrangement presented in FIGS. 20-25 is similar to themixed flow grain dryer system 10 presented in FIGS. 1-19 and thereforeunless specifically stated otherwise herein, the prior teaching anddisclosure shown in FIGS. 1-19 applies equally to the alternativearrangement shown in FIGS. 20-25. That is, the arrangement shown inFIGS. 20-25 is configured to be used with the same or similar pair ofgrain columns 22 having exterior wall 24, interior wall 26, and plenum28; loading system 30; wet hold section 32; mixed-flow heating section34; tempering section 36; cross-flow cooling section 38; unloadingsystem 40; air handling system 42 having a fan system 44, a heatingsystem 46 and louvers 48; and a support system 50, among othercomponents, with the different being changes to outer most ducts 202 ofinlet ducts 88 and/or exhaust ducts 90 as is described herein. Notably,the arrangement shown in FIGS. 20-25 may be used with any mixed flowgrain dryer, and not just a mixed flow grain dryer with vacuum cool asis shown in FIGS. 1-18.

Outer Most Ducts 202

In one or more arrangements, outer most ducts 202 of mixed flow graindryer system 194 are configured to reduce the bridging of grain betweenend walls 52 and the outer most ducts 202. Outer most ducts 202 areformed of any suitable size, shape and design and are configured toallow the flow of heated air through the grain in grain column 22 ofheating section 34 so as to facilitate gentle heating and drying of thegrain while also inhibiting bridging of grain between end walls 52 andthe outer most ducts 202. In the arrangement shown, as one example,outer most ducts 202 have an elongated shape extending from a first endat the exterior wall 24 of grain column 22 to a second end at interiorwall 26 of grain column 22. That is, outer most ducts 202, like allother inlet ducts 88 and exhaust ducts 90 extend across the grain columnand connect to interior wall 26 and exterior wall 24.

In this example arrangement, when viewed from the end, outer most ducts202 are generally triangular shaped members having an outer wall 204 andan inner wall 206, which are jointed together at a peak 208. In thisexample arrangement, inner wall 206 extends outward and downward fromthe peak 208 at an angle away from end wall 52, similar to walls 92 ofthe other inlet ducts 88 and exhaust ducts 90.

In the arrangement shown, as one example, outer most ducts 202 areformed of what are known as right-triangles when viewed from an end.That is, the outer wall 204 extends in a generally vertical manner andextends in an approximate perpendicular alignment to the open bottom endof the outer most duct 202, thereby forming an approximate 90° angle orright-angle between the outer wall 204 and the open bottom wall of theouter most duct 202, which gives the right triangle its name. The innerwall 206 then serves as the hypotenuse of the right triangle connectingto the upper end of outer wall 204 at peak 208 and connecting at itslower the open bottom end. Any other configuration or design is herebycontemplated for use for outer most duct 202.

In this example arrangement, outer walls 204 of outer most ducts 202extend in a generally vertical downward fashion from peak 208. That is,this outward most duct 202 includes an outer wall 204 that extends inapproximate parallel spaced relation to the interior facing side of endwall 52 that defines the end of grain column 22 between interior wall 26and exterior wall 24. In this way, the use of outward most duct 202 doesnot form a narrowing area, or pinch-point, between the outward most duct202 and the interior facing surface of end wall 52 of grain column 22.In this way, grain does not have an opportunity to compact or clump upand form bridged grain 200. As such, in this way, bridge reducing mixedflow grain dryer 198 provides an improved mixed flow grain dryer that isnot susceptible of getting plugged by bridged grain 200 between theoutward most duct 202 and end wall 52.

In the example arrangement shown, ducts 88/90 in rows 210/212 areequally spaced from each other by a distance X across grain column 22.In this example, arrangement, the vertical orientation of outer wall 204of outward most duct 202 permits outward most duct 202 to also beseparated from end wall 52 of grain column 22 by distance X, therebypreventing bridging of grain. (In contrast, the distance between theouter lower end of outer wall 204 of outward most duct 202 in FIG. 19 is½*X). In this way, the use of outward most ducts 202 with vertical ortruncated outer walls 204 are no more restrictive than the other inletducts 88 and exhaust ducts 90 at any other part of the mixed flow graindryer system 10.

However, embodiments are not so limited. Rather, it is contemplated thatducts 88/90 in rows 210/212 may be separated from each other greater orlesser distances which may be uniform or non-uniform. Furthermore, it iscontemplated that outer most ducts 202 may be separated from end walls52 of grain columns by greater or lesser distances which may bedifferent from the distance separating ducts 88/90 in rows 210/212.

Although the arrangements are primarily shown and described withreference to bridge reducing mixed flow grain dryer 198 having anoutward most duct 202 with a vertical extending outer wall 204,embodiments are not so limited. Rather, it is contemplated that in somevarious arrangements, outer wall 204 of outward most duct 202 may beoriented at various slopes or any slope configured to prevent grain frombridging between outer wall 204 and end wall 52 of grain column 22. Forexample, in some arrangements, outward most duct 202 has an inner wall206 having a first slope (e.g., that is approximately the same as theslope of walls 92 of other ducts 88/90) and an outer wall 204 having asecond slope that is greater than the first slope. The increased secondslope of outer wall 204 helps to inhibit bridging of grain.

In the arrangement shown, as one example, inlet ducts 88 and exhaustducts 90 are arranged in alternating horizontal rows of inlet ducts 210and horizontal rows of exhaust ducts 212. In this example arrangement,due to the particular spacing and dimensions, all outward most ducts 202happen to be in the rows of inlet ducts 210. However, embodiments arenot so limited. Rather, it is contemplated that, in variousarrangements, the outer most ducts 202 may be configured to operate asinlet ducts 88, as exhaust ducts 90, or with some outer most ducts 202operating as inlet ducts 88 and others operating as exhaust ducts 90.

Furthermore, it is contemplated that, in various embodiments, inletducts 88 and exhaust ducts 90 may be positioned in any arrangement alonginterior wall 26 and exterior wall 24. For instance, as one alternativeexample, inlet ducts 88 and exhaust ducts 90 may be arranged inalternating columns of inlet ducts 88 and columns of exhaust ducts 90.

From the above discussion it will be appreciated that the mixed-flowgrain dryer with cross-flow heat recovery system presented hereinimproves upon the state of the art. More specifically, and withoutlimitation, it will be appreciated that the mixed-flow grain dryer withcross-flow heat recovery system presented herein: is efficient to use;facilitates heat recovery; reduces fuel consumption; is gentle on grain;does not damage grain when drying; does not overly dry grain;facilitates cooling of grain before it is discharged; evenly driesgrain; does not have variability of grain quality across the graincolumn; does not have variability of moisture across the grain column;can be precisely controlled; that provides optimum results; thatfacilitates unloading of grain from the dryer at a single point; isrelatively compact; is relatively inexpensive; can be used with allkinds of grain; that minimizes maintenance; requires less cleaning; iscleaner to use than prior art systems; is safe to use; reduces thepotential for a fire; requires less air pressure; requires less airflow; provides improved grain quality; is easy to use; has a robustdesign; is high quality; incorporates the benefits of mixed-flow graindying with the benefits of cross-flow vacuum cooling; and/or reducesbridging of grain among countless other advantages and improvements.

It will be appreciated by those skilled in the art that other variousmodifications could be made to the device without parting from thespirit and scope of this disclosure. All such modifications and changesfall within the scope of the claims and are intended to be coveredthereby.

What is claimed:
 1. A mixed flow grain dryer system, comprising: aninterior wall; an exterior wall; the interior wall and exterior wallpositioned in spaced relation to one another thereby forming a graincolumn between the interior wall and the exterior wall; an end wall; theend wall enclosing an end of the grain column; a set of ducts extendingacross the grain column; an outward most duct extending across the graincolumn; the outward most duct positioned between the end wall of thegrain column and the set of ducts; wherein the outward most duct has afirst wall facing away from the end wall of the grain column and asecond wall facing toward the end wall of the grain column; wherein thesecond wall has a greater slope than a slope of the first wall; whereinthe greater slope of the second wall of the outward most duct helps toreduce bridging of grain between the outward most duct and the end wallof the grain column.
 2. The system of claim 1, wherein the second wallof the outward most duct is approximately vertical.
 3. The system ofclaim 1, wherein the set of ducts have a pair of sloped walls having aslope approximately equal to the slope of the first wall of the outwardmost duct.
 4. The system of claim 1, wherein the set of ducts aretriangular shaped.
 5. The system of claim 1, wherein the first wall andsecond wall of the set of ducts curve downward.
 6. The system of claim1, wherein the outward most duct and the set of ducts have an openbottom end.
 7. The system of claim 1, wherein the outward most ductconnects to an exhaust vent in the exterior wall.
 8. The system of claim1, wherein the outward most duct connects to an inlet vent in theinterior wall.
 9. The system of claim 1, wherein the set of ductsconnect to exhaust vents in the exterior wall.
 10. The system of claim1, wherein the set of ducts connect to inlet vents in the interior wall.11. A mixed flow grain dryer system, comprising: a grain column; thegrain column formed by an interior wall and an exterior wall; an endwall enclosing an end of the grain column between the interior wall andthe exterior wall; a set of ducts positioned within the grain column; anoutward most duct; the outward most duct positioned between the end wallof the grain column and the set of ducts; the outward most duct havingan outer wall and an inner wall; wherein the outer wall of the outwardmost duct faces the end wall of the grain column; wherein the outer wallof the outward most duct extends in a generally vertical manner; whereinthe outer wall of the outward most duct helps to reduce bridging ofgrain between the outward most duct and the end wall of the graincolumn.
 12. The system of claim 11, wherein the outer wall of theoutward most duct extends in approximate parallel spaced relation to theend wall of the grain column.
 13. The system of claim 11, wherein theset of ducts have a pair of sloped walls having a slope equal to theslope of the inner wall of the outward most duct.
 14. The system ofclaim 11, wherein the set of ducts are triangular shaped.
 15. The systemof claim 11, wherein the inner wall and outer wall of the outer mostduct curve downward.
 16. The system of claim 11, wherein the outwardmost duct and the set of ducts have an open bottom end.
 17. The systemof claim 11, wherein the outward most duct connects to an exhaust ventin the exterior wall.
 18. The system of claim 11, wherein the outwardmost duct connects to an inlet vent in the interior wall.
 19. The systemof claim 11, wherein the set of ducts connect to exhaust vents in theexterior wall.
 20. The system of claim 11, wherein the set of ductsconnect to inlet vents in the interior wall.
 21. A mixed flow graindryer system, comprising: an interior wall; an exterior wall; theinterior wall and exterior wall positioned in spaced relation to oneanother thereby forming a grain column between the interior wall and theexterior wall; an end wall; the end wall enclosing an end of the graincolumn; a set of triangular ducts extending across the grain column; anoutward most duct; the outward most duct positioned between the end wallof the grain column and the set of ducts; the outward most duct havingan outer wall and an inner wall; wherein the outer wall of the outwardmost duct faces the end wall of the grain column; wherein the outer wallof the outward most duct extends in approximate parallel spaced relationto the end wall of the grain column; wherein the outer wall of theoutward most duct helps to reduce bridging of grain between the outwardmost duct and the end wall of the grain column.
 22. A mixed flow graindryer system, comprising: an interior wall; an exterior wall; theinterior wall and exterior wall positioned in spaced relation to oneanother thereby forming a grain column between the interior wall and theexterior wall; an end wall; the end wall enclosing an end of the graincolumn; a set of ducts extending across the grain column; an outwardmost duct extending across the grain column; the outward most ductpositioned between the end wall of the grain column and the set ofducts; wherein the outward most duct has a first sloped wall thatextends away from the end wall at an angle from a peak at an upper endto a lower end; wherein the outward most duct has a second wall thatextends approximately vertically from the peak at an upper end to alower end; wherein the approximate vertical alignment of the second wallof the outward most duct prevents narrowing of the space between the endwall and the outward most duct which helps to reduce bridging of grainbetween the outward most duct and the end wall of the grain column. 23.The system of claim 22, wherein the outward most duct and the set ofducts have an open bottom end.